In a toilet flushing system disclosed in German A-26 34 248, a fluid or pressure container with only one diaphragm is attached on the fluid side to a cold- and warm-water fresh water feed for filling with fresh water. The fresh water feed delivers fresh water to a sanitary device with the suitable control setting of the valve arrangement for a flushing or cleansing process. The gas side of the fluid storage container is separated from the fluid side by the elastic or flexible separating diaphragm made of plastic or rubber. The gas cushion of nitrogen or air with a pre-formed bias is present. In a flushing process, the gas cushion delivers the pre-bias pressure to the fluid side, so that the flushing process is induced with high pressure and affords at least identical good cleansing results, as compared with conventional toilet flushing systems, while requiring only a relatively small fresh water volume.
Despite the advantage of the reduction of fresh water required with this known toilet flushing device, pressure surges or peaks occur because of water pressure deviations in the system, which lie below static pressure. The pressure surges or peaks lead to pressure deviations at the end of the flushing process, so that the desired and basic cleansing can no longer be guaranteed, especially with still further reduced flushing water volume. Short filling times, without transmission of pressure points in the water system, when using the known toilet flushing system cannot be attained. Therefore, a structurally larger fluid storage container is required for production of the pre-biasing over the separating diaphragm by means of the gas cushion. This requirement opposes space-saving assembly and construction in toilet flushing systems.
In the toilet flushing system disclosed in German A-35 36 967, a liquid storage container is configured as a cylinder and has a movable piston within it subdividing the cylindrical container into two liquid chambers which can be filled with fresh water. The piston moves back and forth under normal ambient pressure for a flushing cycle. Two flushing processes take place with the same water volume. With the thrusting of one partial water volume out of the cylinder by the piston, the other partial chamber of the cylinder is simultaneously filled with water. When the flushing cycle includes two timed sequential flushing processes, a partial volume of the flushing water is fed to the flushing device during each operation, and improved flushing results are attained. At the same time, with reduced structural size of the flushing assembly in the form of the cylinder with piston, however, a great additional volume of fresh water is required because of the two-cycle flushing cycle.
In the toilet flushing system disclosed in European Patent -A-O 430 521, an elastically flexible diaphragm is blown up in the manner of a balloon to produce the flushing pressure required for a flushing process. Fresh water is fed from the diaphragm bubble into the balloon. For the purpose of a flushing process, the balloon stands under the pressure arising upon contraction of the elastic diaphragm bubble. The bubble again discharges the volumes of fresh water contained therein. In another embodiment of this known toilet flushing system, pre-biasing is attained by a pressure spring which is released abruptly during initiation of a flushing process. Under the spring bias, a piston moves in a cylinder, and drives the water volume previously stored in the cylinder to initiate the flushing process. This known toilet flushing system has a complicated construction, and thus, is expensive to manufacture. In addition, the pre-biasing which can be obtained by the diaphragm bubble and pressure spring is not sufficient to produce sufficiently high flushing pressure for a good cleansing result with a minimum volume of water.
A fluid storage container with a storage container casing subdivided by two separating diaphragms into three partial chambers, in which the one partial chamber is defined by the two separating diaphragms and serves to hold gas and the other two partial chambers are provided to hold a fluid in the form of water or hydraulic oil, is known by experts in many embodiments (German A-1 525 730, German A-3 021 829 and Belgian A-666 221). These known fluid storage containers represent a type of pressure expansion or compensation vessel. The incorporated gas pressure cushion provides pressure and/or temperature compensation in the fluid circuit to which the relevant fluid storage container is connected by its two fluid chambers arranged at the ends. Furthermore, pulses occurring in the fluid system can be attenuated. In another type of known fluid storage container with two separating diaphragms (France A-2 529 290), a volume of fluid guided between the two separating diaphragms is driven by pulse-like application of simultaneous gas pressure surges or peaks in the two other partial chambers. Such partial chambers are defined by the separating diaphragms. This type of fluid storage container represents a type of fluid pump which can transport the fluid especially gently and by pulsing.